/Engine/Plugins/Runtime/RigVM/Source/RigVM/Public/RigVMCore/RigVMRegistry.h
Returns a dispatch factory's singleton function name if that exists.
[FString](API\Runtime\Core\Containers\FString) FindOrAddSingletonDispatchFunction ( [UScriptStruct](API\Runtime\CoreUObject\UObject\UScriptStruct) * InFactoryStruct )